Steam Driven Engine

ABSTRACT

An engine includes a piston and a stator housing. The stator housing includes a channel in which the piston is disposed, an input port that is adapted to receive a working fluid into the channel, and an output port that is adapted to exhaust the working fluid from the channel. The channel is arranged such that the piston is able to move continuously in a single direction within the channel.

CROSS-REFERENCE TO RELATED APPLICATION

This is related to, and claims the benefit under 35 USC §119(e) of U.S. Provisional Application for Patent No. 60/837,341, which was filed on Aug. 11, 2006.

FIELD OF THE INVENTION

The invention relates to steam engines, particularly to positive-displacement rotary steam engines, which operate and perform work as powered by vibrational energy and thermal expansion of a working fluid within a fluid container to provide the necessary thrust/displacement to induce rotation of a prime mover.

BACKGROUND OF THE INVENTION

The most common engine in use today is the internal combustion engine using some sort of petroleum-based derivative as a fuel. Due to problems including exhaust pollution, the availability and renewability of fuel, and durability of the engine, alternatives to this common engine would be advantageous.

Examples of steam engines have been known for many years, although they are not in widespread use. In a conventional steam engine, a working fluid is filled into a fluid container (also known as a pressure vessel), the fluid is heated and vaporized by a heating device (also known as a flash tube generator), transduced into kinetic motion, and the vaporized steam is then cooled and condensed to change a pressure in the fluid container. Pistons or similar implements in the fluid container are moved by the steam generated by the heating device, to generate the kinetic energy. In other embodiments, the working fluid is moved in the working channel by expansion pressure of the vaporized working fluid and the pistons are driven by the fluid movement to generate the kinetic energy.

The present invention is an embodiment of a steam engine that provides certain advantages over conventional embodiments, as will be apparent to those of skill in the art.

BRIEF SUMMARY OF THE INVENTION

According to an aspect of the invention, an engine includes a piston and a stator housing. The stator housing includes a channel in which the piston is disposed, an input port that is adapted to receive a working fluid into the channel, and an output port that is adapted to exhaust the working fluid from the channel. The channel is arranged such that the piston is able to move continuously in a single direction within the channel.

Preferably, the channel forms a closed loop within the stator housing. For example, the closed loop can define a circle. The engine also preferably includes a shaft, in which case the piston is in communication with the shaft such that the shaft rotates about a longitudinal axis of the shaft consistent with movement of the piston through the channel. The engine can also include a counter-element acting as a counter-balance that is in communication with the shaft so as to move in a path corresponding to a path of movement of the piston through the channel.

The engine can include more than one piston. For example, the piston described above can be a first piston, and the engine can also include a second piston disposed within the channel and in communication with the shaft such that the shaft rotates about a longitudinal axis of the shaft consistent with movement of the second piston through the channel. In this embodiment, the stator housing can also include a second input port and a second output port. In this case, the shaft is disposed at the center of the circle defined by the closed loop of the channel, and the first piston and the second piston are disposed within the channel at a relative fixed angle with respect to the position of the shaft. Likewise, the first input port and the second input port are preferably disposed within the channel at the same relative fixed angle with respect to the position of the shaft, and the first output port and the second output port are disposed within the channel at the same relative fixed angle with respect to the position of the shaft. For example, the fixed angle can be substantially 180 degrees, that is, such that the pistons and ports are arranged on opposite sides of the circular channel.

According to another aspect of the invention, a machine includes the engine described above, and a workpiece coupled to the shaft. Rotational energy of the shaft applied to the workpiece translates to work performed by the machine.

According to a preferred embodiment of the invention, the engine also includes a fluid source in communication with the input port and the output port. The fluid source includes a reservoir for holding at least some of the fluid, and a heater, such as a boiler, adapted to raise the temperature of the fluid to a vaporous state. For example, the fluid source can be adapted to provide heated, vaporous fluid to the channel via the input port to cause the piston to move through the channel ahead of the fluid. In this case, the output port can be arranged to allow the fluid to exhaust to the reservoir after the piston has moved through the channel past the output port.

The engine can also include a valve coupled to the output port. Preferably, the valve is biased so as to substantially close an opening of the output port. The valve can be adapted, for example, to open the opening of the output port when urged by a front portion of the piston when the piston moves through the channel. For example, the valve can include an actuation surface that is adapted to open the output port when urged by a front portion of the piston when the piston moves through the channel.

Alternatively, the engine can also include an eccentric element, such as a cam, coupled to the shaft so as to rotate with rotational movement of the shaft and having an irregular shape in the plane of rotation. In this case, the valve includes an actuator that extends into the path of rotation of a working portion of the eccentric element. The eccentric element is adapted to impart a reciprocal motion to the actuator as the eccentric element rotates while the working portion of the eccentric element is in contact with the actuator so as to urge open the opening of the output port in accordance with the relative position of the piston within the channel.

As another alternative, the engine can also include a first geared element and a second geared element. The first geared element is coupled to the shaft so as to rotate with rotational movement of the shaft and has a first pattern of gear teeth. The second geared element is coupled to the valve and has a second pattern of gear teeth. The first and second geared elements are adapted to selectively couple the first and second patterns of gear teeth in correspondence with the rotational movement of the shaft so as to open and close the opening of the output port in accordance with the relative position of the piston within the channel.

Preferred embodiments of the invention feature a central entry, radial exit design for supplying the working fluid to the channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary single-piston design of the invention.

FIG. 2 is a schematic diagram of an exemplary dual-piston design of the invention.

FIG. 3 is a schematic diagram of an exemplary eccentric slide valve design of the invention.

FIG. 4 is a schematic diagram of an exemplary cylinder valve design of the invention.

FIG. 5 is a schematic diagram of an exemplary swinging-door valve design of the invention.

FIG. 6 is a schematic diagram of an exemplary wedge valve design of the invention.

FIG. 7 is a schematic diagram of an exemplary arced fluid path design of the invention.

FIG. 8 is a diagram showing an exemplary clam-shell stator design of the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a cut-away schematic diagram of the invention for purposes of explanation of the basic principles of its operation. In this figure, a positive displacement rotary piston steam engine 1 includes a piston 2 in communication with a shaft 3. The piston 2 is disposed within a channel 4 of a stator housing 5. FIG. 1 shows only a cut-away view of the stator housing, with an inner boss 6 defining an inner wall of the channel 4. An outer boss around the outer periphery of a side wall 7 of the stator housing 5 defines an outer wall of the channel 4. The side wall 7 of the stator housing 5 also includes an input port 8 that receives working fluid into the channel 4 through the back end of the piston 2, and an output port 9, which exhausts the working fluid from the channel 4.

The working fluid is supplied by a fluid source (not shown) in communication with the input port 8. Preferably, the fluid source includes a heater that heats the working fluid to vaporization, and the heated fluid enters the channel through the input port 8, developing motive force that pushes the piston 2 around the path defined by the channel 4. The working fluid is exhausted from the stator through the output port 9, at which time it is preferably condensed and collected in a reservoir of the fluid source (not shown) before reaching the input port 8 once again. The reservoir preferably includes a provision for pressure release of the exhaust fluid, which is preferably recycled through the heater for reuse in the channel. It is contemplated that the working fluid will be water, or primarily water conditioned through a process or with additives (lubricants, anti-corrosives, etc.), which as steam will provide the motive force behind the piston 2. The piston 2 is sealed against the bosses and sidewalls of the stator housing 5 forming the channel 4 by conventional seals known to those of skill in the art, to provide a fit that is substantially fluid-tight while allowing movement of the piston 2 through the channel 4. Bearings and/or lubricants on any of the surfaces can be utilized as appropriate, as known to those of skill in the art.

The piston 2 can be coupled to the shaft 3, for example, by a piston arm 10, which is connected to the piston 2 at a sealed groove in the inner boss 6, allowing for movement of the piston arm 10 with the movement of the piston 2 and translating the motion of the piston 2 through the channel 4 into rotational movement of the shaft 3 about the longitudinal axis of the shaft 3. A working fluid input path 31 is disposed as a hollow passage within the shaft 3, piston arm 10, and piston 2, providing a conduit through which the working fluid is provided under pressure from the fluid source to the output port 8 on the back end of the piston 2. Via this fluid path 31, the vaporized working fluid passes from the fluid source to the output port 8, where it propels the piston 2 forward through the channel in the working direction.

Preferably, the piston 2 is sealed against the walls of the channel 4, in part by the selection of material and shape of the piston 2. Preferably, the piston 2 is made from a resilient material that expands to form a seal against the channel 4 under the heat and pressure of the working fluid. Suitable lubrication, such as water-soluble oil, or other surface treatment is preferably applied to the piston 2 and/or channel 4 to provide contact characteristics conducive to continuous flowing motion.

A distal end of the shaft 3 can be coupled to the workpiece of a machine that includes the engine 1 or that is external to the engine 1. In this way, rotational energy of the shaft 3 can be used to perform work by the machine. A counter-element 11 can also be coupled to the shaft 3, for example by a second arm 12. This counter-element can provide balance to the piston assembly as the piston 2 moves through the chamber 4. The counter-element 11 preferably has a shape and mass suitable for balancing the piston 2, and preferably is located opposite the piston 2 across the stator housing 5, although the exact shape, mass, and relative location can be tuned as known by those of skill in the art to fit the particular application. The counter-element acts as a counter-balance to equally and oppositely balance the thrust of the piston to smooth the torque of the engine.

FIG. 2 shows a similar embodiment of the engine 1. In this embodiment, dual pistons 2, 13 are used. The second piston 13 of this embodiment replaces the counter-element of the previous embodiment, and is coupled to the shaft 3 by a second piston arm 14. The dual-piston arrangement can use the single input port 8 and output port 9 of the previous embodiment, or it can utilize dual input and output ports for improved efficiency in some applications, or dual output ports can be used with a shared input port. Preferably, the pistons are offset from each other by 180 degrees, as are the respective ports, although other offset angles for the pistons and ports are contemplated, depending on the particular application.

Preferably, the engine 1 includes a valve arrangement to prevent the working gas in the channel 4 from passing directly from the input port 8 to the output port 9, and to maintain the proper relative pressures at the front and back ends of the piton 2 to allow free and consistent motion of the piston 2 through the channel 4. This valve can be disposed to cover the output port 9, or as a barrier within the channel 4. The actual valve geometry depends on the piston geometry, which in turn determines the duration of the exhaust cycle.

An exemplary valve is shown in FIG. 3. The eccentric slide valve 15 is disposed in the channel at a position that closes off the output port from the front end of the piston 2 until the piston is about to pass the output port 9. Movement of the valve 15 is controlled by the eccentric element 16, which is keyed to the rotor assembly, for example at the shaft 3, to rotate in the plane of the stator sidewall 7 in accordance with the timing of the piston 2. As shown, the eccentric element 16 has an irregular shape, including a central portion and a working portion 19 that extends from the central portion. The valve 15 includes an actuator, preferably including a bearing, that extends through a slot 18 in the sidewall 7 from the channel to the exterior of the sidewall 7, proximate to the eccentric element 16. Through most of the piston cycle, the valve 15 is in position to close off the channel, and preferably is biased to remain in this position. As the eccentric element turns, the working portion 19 engages the actuator 17 when the timing is appropriate to open the valve, that is, when the piston 2 will pass through the valve region of the channel. As the extended working portion engages the actuator with force sufficient to overcome the valve bias, it urges the actuator along the slot 18, lifting the valve to open the channel. In this embodiment, the stator housing includes a slot or other orifice to accommodate the upward movement of the valve. As the peak of the working portion 19 engages the actuator, the valve is in its most completely opened position, at least to an extent necessary to allow the piston to pass. Once past the peak of the working portion 19, the actuator 17 moves back down the slot until the valve 15 returns to the closed position, and the cycle repeats through the rotor cycle to allow necessary backpressure so that the piston can continue to move forward. Those of skill in the art will recognize that the profile of the working portion 19 of the eccentric element 16 can be changed to effectuate the timing and extent of the opening and closing of the valve 15, and the invention is not limited to the particular shape shown in this exemplary embodiment.

FIG. 4 shows an embodiment of the engine 1 utilizing a cylinder valve in which the port region of the channel is enclosed within a cylinder 21 that provides for opening and closing of the output port according to the position of the piston 2 within the channel. A gear keyed to the rotor assembly at, for example, the shaft 3 engages a second gear assembly 22 keyed to the valve, preferably disposed at the exterior of the stator housing, at the port region. In this embodiment, the rotor-keyed gear has teeth only over a particular portion of the periphery, corresponding to the location of the piston within the channel when the valve 20 is to be opened to allow passage of the piston 2 and/or open the output port. When these teeth engage the teeth of the valve-keyed gear, the appropriate opening is made to allow necessary backpressure so that the piston can continue to move forward.

FIG. 5 shows a swinging-door valve 23 used to appropriately open and close the output port 9 opening. In this embodiment, the piston 2 includes a valve engagement nose 24, preferably wedge- or conically-shaped. The valve 23 includes an actuation portion 25 and a closure portion 26, joined at a hinge 27. Before the piston 2 reaches the port region of the channel during the rotor cycle, the closure portion 26 seals off the output port 9, and the actuation portion 25, arranged at an angle to the closure portion 26, extends into the channel, in the path of the moving piston 2. Preferably, the valve is biased in this closed position. As the piston approaches, the nose 24 engages the actuation portion 25 in advance of the arrival of the back end of the piston 2, which is sealed against the channel walls. The nose 24 engages the actuation portion 25 with sufficient force to overcome the valve bias, and thereby urges the closure portion 26 of the valve 23 to swing open about the hinge 27. After the piston has passed the valve 23, the bias urges the valve 23 such that it the closure portion 26 swings shut, and the cycle continues.

A wedge valve arrangement is shown in FIG. 6. This arrangement is similar to the swing-door valve arrangement described above, with the valve 28 arranged in the outer boss 30 of the stator housing. The piston nose 29 takes the shape of a wedge, preferably with a curved outer surface as shown. The curved surface of the nose 29 engages the valve in a fashion similar to that of the swinging-door valve, urging the valve open against a bias to allow the working gas to exhaust from the channel, and closing after the piston has passed.

The stator housing 5 also preferably includes an auxiliary output port 32. This port 32 comes into play when the output port 9 is closed as the piston 2 passes. When the output port 9 is closed, there must be some way for the built-up pressure in the channel 4 ahead of the piston 2 to be released if piston motion is to continue. The auxiliary output port 32 allows for release of this pressure. This port can remain open at all times, or can be timed to open as the output port 9 is closed, through the use of a valve that is complementary to the output port valve. The relative position of the output port 9 and the auxiliary output port 32 shown in the figures is exemplary and is not intended as a limitation on the scope of the invention.

FIG. 7 shows an alternative embodiment of the piston arm 10. This piston arm 10 provides an arced fluid channel 31 to optimize kinetic forces of the working fluid as it exits the input port 8.

For ease of explanation, only one side of a cut-away portion of the stator housing has been shown. FIG. 8 shows a cross-section of the housing 5, so that elements of both sides of the housing are shown. As shown, inner and outer bosses mate to form the channel between, with a gap in the inner boss pair to accommodate the piston arms. This gap is sealed when the piston arm is in place through the use, for example, of an annular sealing element (not shown).

Exemplary and preferred embodiments of the invention have been described. The description of these particular embodiments, however, is not intended to limit the scope of the invention. Those of skill in the art will recognize that certain details of the invention as described herein, such as piston geometry, the relative dimensions of components of the invention, number and relative locations of the pistons, valves, channels, and other components, as well as other details can be modified without departing from the scope of the invention as contemplated by the inventor. 

1. An engine, comprising: a piston; and a stator housing; wherein the stator housing includes a channel in which the piston is disposed; an input port that is adapted to receive a working fluid into the channel; and an output port that is adapted to exhaust the working fluid from the channel; wherein the channel is arranged such that the piston is able to move continuously in a single direction within the channel.
 2. The engine of claim 1, wherein the channel forms a closed loop within the stator housing.
 3. The engine of claim 2, wherein the closed loop defines a circle.
 4. The engine of claim 3, further comprising a shaft, wherein the piston is in communication with the shaft such that the shaft rotates about a longitudinal axis of the shaft consistent with movement of the piston through the channel.
 5. The engine of claim 4, further comprising a counter-element in communication with the shaft so as to move in a path corresponding to a path of movement of the piston through the channel.
 6. The engine of claim 4, wherein the piston is a first piston, the engine further comprising a second piston disposed within the channel and in communication with the shaft such that the shaft rotates about a longitudinal axis of the shaft consistent with movement of the second piston through the channel.
 7. The engine of claim 6, wherein the input port is a first input port; and the output port is a second output port; the stator housing further including a second input port and a second output port.
 8. The engine of claim 7, wherein the shaft is disposed at the center of the circle defined by the closed loop of the channel, the first piston and the second piston are disposed within the channel at a relative fixed angle with respect to the position of the shaft, the first input port and the second input port are disposed within the channel at the relative fixed angle with respect to the position of the shaft, and the first output port and the second output port are disposed within the channel at the relative fixed angle with respect to the position of the shaft.
 9. The engine of claim 8, wherein the fixed angle is substantially 180 degrees.
 10. A machine, comprising the engine of claim 4 and a workpiece coupled to the shaft.
 11. The engine of claim 1, further comprising a fluid source in communication with the input port and the output port, wherein the fluid source includes a reservoir for holding at least some of the fluid, and a heater adapted to raise the temperature of the fluid to a vaporous state.
 12. The engine of claim 11, wherein the fluid source is adapted to provide heated, vaporous fluid to the channel via the input port to cause the piston to move through the channel ahead of the fluid.
 13. The engine of claim 12, wherein the output port is arranged to allow the fluid to exhaust to the reservoir after the piston has moved through the channel past the output port.
 14. The engine of claim 13, further comprising a valve coupled to the output port.
 15. The engine of claim 14, wherein the valve is biased so as to substantially close an opening of the output port.
 16. The engine of claim 15, wherein the valve is adapted to open the opening of the output port when urged by a front portion of the piston when the piston moves through the channel.
 17. The engine of claim 16, wherein the valve includes an actuation surface that is adapted to open the opening of the output port when urged by a front portion of the piston when the piston moves through the channel.
 18. The engine of claim 15, further comprising an eccentric element, coupled to the shaft so as to rotate with rotational movement of the shaft and having an irregular shape in the plane of rotation; wherein the valve includes an actuator that extends into the path of rotation of a working portion of the eccentric element; wherein the eccentric element is adapted to impart a reciprocal motion to the actuator as the eccentric element rotates while the working portion of the eccentric element is in contact with the actuator so as to urge open the opening of the output port in accordance with the relative position of the piston within the channel.
 19. The engine of claim 18, wherein the eccentric element is a cam.
 20. The engine of claim 14, further comprising: a first geared element, coupled to the shaft so as to rotate with rotational movement of the shaft and having a first pattern of gear teeth; and a second geared element, coupled to the valve and having a second pattern of gear teeth; wherein the first and second geared elements are adapted to selectively couple the first and second patterns of gear teeth in correspondence with the rotational movement of the shaft so as to open and close the opening of the output port in accordance with the relative position of the piston within the channel. 